Discovery of a big void in Khufu’s Pyramid by observation of cosmic-ray muons

An international team of scientists has discovered a large hidden cavity within Egypt’s Great Pyramid of Giza, and they did it by looking for muons — particles sent to Earth by cosmic rays from space.

The mysterious cavity, described Thursday in the journal Nature, is at least 30 meters long. And though the researchers aren’t sure whether it’s straight or inclined, whether it’s one large space or a series of smaller ones, the discovery has already triggered interest among archaeologists as to the purpose of the void.

“What we are sure about is that this big void is there,” said Mehdi Tayoubi, president of the nonprofit Heritage Innovation Preservation Institute in Paris, which led the effort. ”But we need to understand [it] better.”1

Nature (2017) doi:10.1038/nature24647 Received 12 October 2017 Accepted 24 October 2017 Published online 02 November 2017

The Great Pyramid or Khufu’s Pyramid was built on the Giza Plateau (Egypt) during the IVth dynasty by the pharaoh Khufu (Cheops), who reigned from 2509 to 2483 BC1. Despite being one of the oldest and largest monuments on Earth, there is no consensus about how it was built2,3. To better understand its internal structure, we imaged the pyramid using muons, which are by-products of cosmic rays that are only partially absorbed by stone4–6. The resulting cosmic-ray muon radiography allows us to visualize the known and potentially unknown voids in the pyramid in a non-invasive way. Here we report the discovery of a large void (with a cross section similar to the Grand Gallery and a length of 30 m minimum) above the Grand Gallery, which constitutes the first major inner structure found in the Great Pyramid since the 19th century 1. This void, named ScanPyramids Big Void, was first observed with nuclear emulsion films7–9 installed in the Queen’s chamber (Nagoya University), then confirmed with scintillator hodoscopes10,11 set up in the same chamber (KEK) and re-confirmed with gas detectors12 outside of the pyramid (CEA). This large void has therefore been detected with a high confidence by three different muon detection technologies and three independent analyses. These results constitute a breakthrough for the understanding of Khufu’s Pyramid and its internal structure. While there is currently no information about the role of this void, these findings show how modern particle physics can shed new light on the world’s archaeological heritage.